in case you haven't, try this....
in Control Panel (change View By to icons), click Network and Sharing Centre > Change advanced sharing settings.
in all the sections, select Turn on network discovery, turn on file and printer sharing and in the All Networks section, Turn off password-protected sharing.
these settings can be fine tuned for your particular needs later, let's just get it working first.
click Save Changes.
repeat on other PC.
now in File Explorer, click Network in the left column.
that should show all your connected devices.
you should see whatever your laptop is called, and whatever your desktop is called.
drill down on the one you want to access and try to open a folder, if no success you may also have to setup file sharing permissions.
on that PC, right click the folder, Properties, Sharing, Share, use the drop down menu to pick Everyone, Add, change Read to Read/Write, click Share.
again, repeat accordingly on each PC for whatever sort of access you need.
then, perhaps, your AV's firewall may need tweaking.
that should get you started. if successful you can fine tune the security settings if you need to, but in a Private, home use, network, there may not be a requirement to tighten things up too much.
